Sewing machine with a printed circuit switch and variable speed control means

ABSTRACT

A sewing machine is provided with a printed circuit switch and a cooperating control means whereby the mechanisms thereof can be selectively operated with variable speed in a forward direction or in a reverse direction such that the conventional handwheel of a sewing machine can be eliminated. Additionally, a sewing machine may be operated without the use of the conventional operator-actuated foot controller connected to the machine.

United States Patent [1 1 Fersch et al. Jan. 8, 1974 [54] SEWING MACHINE WITH A PRINTED 3,141,429 7/1964 Momberg et al. 112/220 CIRCUIT SWITCH AND VARIABLE SPEED 3,319,591 5/1967 Hamlett 112/220 CONTROL MEANS [75] Inventors: Harry Fersch, Lakewood; Walter P i E i r I-[ Hampton Hunter Heinz P Rockaway, both of Attorney- Marshall .1. Breen and Chester A. Williams, NJ. Jr. [73] Assignee: The Singer Company, New York,

57 ABSTRACT [22] Filed: Nov. 24, I972 [21] AppL No: 309,318 A sewing machine is rovided with a printed circuit switch and a cooperating control means whereby the g mechanisms thereof can be selectively operated with [52] CI. 112/220 variable speed in a forward direction or in a reverse [51] Int. Cl D05b 69/14 dire tion su h that the conventional handwheel of a Field of sealdi 219 sewing machine can be eliminated. Additionally, a 9 A sewing machine may be operated without'the use of the conventional operator-actuated foot controller [56] References Cited connected to the machine.

PAIENTEDJAN amq sum 2 [IF 2 I 1 SEWING MACHINE WITH A PRINTED CIRCUIT SWITCH AND VARIABLE SPEED CONTROL MEANS BACKGROUND OF THE INVENTION The present invention relates to sewing machines, and in particular, to the elimination of the sewing machine handwheel and replacing it with a printed circuit switch and control arrangement without eliminating the ability of an operator to lower or raise slowly the needle ofthe sewing machine.

In the process of sewing various types of articles of clothing it becomes necessary to stop the sewing machine and change the orientation of the material without removing the needle from the work'being sewn. Consequently, it is to the operators advantage to be able to maintain the sewing machine needle in the work piece while changing the orientation of the work. It also is an advantage, under certain circumstances, to be able to raise the needle out of the work once the machine has stopped so that the work may be removed SUMMARY or THE INVENTION An improved sewing machine, built in accordance with the principles of the present invention, has a frame including a bedand a hollow standard rising therefrom, stitch forming instrumentalities and work feeding mechanism, a main-shaft operatively connected to the stitch forming instrumentalities and the work feeding mechanism, an electric motorlocated within frame and operatively connected to the main-shaft, an operatoractuated foot controller for regulating the speed of operation of the motor, solid state circuit means coupled to the motor and controller and having terminals adapted to be connected to an external source of electrical energy, and variable speed switch means fixedly mounted within the sewing machine frame and coupled to the motor and the solid state circuit means for driving the motor in a forward and reverse direction.

DESCRIPTION OF THE DRAWING FIG. 1 is a front view of a sewing machine in which I the present invention is embodied;

FIG. 2 is an end view ofa sewingmachine incorporating the principles of the present invention with the end cover removed; 7

FIG. 3 is a partial cross sectional view in elevation,

taken substantially along the line 3-3 of the sewing DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and in particular to FIG. I, there is shown a sewing'machine 10. The sewing machine 10, in which the present invention is incorporated, comprises a frame 11 which has a substantially rectangular hollow base 12 having at its upper side a work supporting surface or bed 14 including therein a throat plate 16. Suitably secured upon the hollow base 12 is a vertically disposed hollow standard 18 which carries an overhead bracket-arm 20 terminating in a hollow head 22 in which is mounted a reciprocatory needle bar 24 carrying a needle 25. Also included in the hollow head 22 is a presser bar 26 which is terminated in a presser foot 28. Additionally included in the sewing machine 10 is a loop taker 30, a thread tension control 32 and a spindle 34 for retaining a spool of thread, and an electrical drive motor 35 which is coupled, via a geared coupling means 37, to a drive shaft 39. All of the items mentioned above are found on a conventional sewing machine as well as are stitch forming instrumentalities and work feeding mechanisms 45, all well known in the art.

In a preferred embodiment, in'accordance with the principles of the present invention, the standard 18 of the sewing machine 10 is provided with an on-off power switch 36 and an actuating means 38 in the form of knob. The knob 38 is provided with an extension 33 for ease of operation. I

'The base 12 of the preferred embodiment is provided with a socket 40, which is adapted to be connected, via a cable and mating plug 41, to an operator actuated foot controller 42, shown in FIG. 5, and the AC energy source, not'shown. The base 12 is also provided with a relay 43 and a solid state circuit means 44, which is substantially the same electrically as the solid state circuit means provided in the foot controller 42. The operation of the relay 43 and the circuit means 44 will be explained hereinafter.

An end view of a preferred embodiment of the sewing machine 10 is shown in FIG. 2 with the cover plate 46 removed. The cover plate 46 is mounted to the hollow standard 18, via screws 47 and 48, as shown in FIG. 3. With the cover plate 46 removed a printed circuit switch mechanism 50 and a control means 52 are exposed.

The printed circuit switch mechanism 50, in the preferred embodiment, includes an insulated board member 54, which is mounted to the frame of the sewing machine via two screws 56 and 58. A plurality .of conductive strips or contacts 59 and 60 are provided on the insulated board member 54 in a conventional member, which forms a printed circuit as is well known in the art. The contacts 59 and 60 are arranged in accordance with the circuit requirements of the solid state circuit means 44 shown in FIG. 5, and are coupled thereto by wires 63.

The insulated board member 54 is provided with a hole 62 into which is mounted a collar 64 that contains a flange 66 which functions to rigidly support the insulated board member 54, thereby preventing it from flexing.

The collar 64 (FIG. 3) is provided with a hole 68 in which a shaft 70 is journaled. One end of shaft 70 has a gear 72 rigidly affixed thereto. The other end of shaft 70 is provided with threads upon which a metal arm 74 is threaded. In close juxaposition with the metal arm 74 is a contactor arm 76, which is made of a nonconducting material (insulator) and into which is fixedly mounted conductive spring finger contacts 78. The spring finger contacts are adapted to cooperate with the electrical conducting contacts 59 and 60 provided on the insulated board member 54. The electrical contacts and are coupled to the electrical circuit means, via conducting wires 63. The contactor arm 76 is attached to shaft by means of a setscrew 86 and is pinned to the metal arm 74 by a pin 88. Contactor arm 76 is also provided with two wheels and 92 which are rotatably retained within the contactor arm 76 by pins 94 and 96 respectively. Wheels 90 and 92 provide rolling contact with a rocker arm 98.

Rocker arm 98 is provided with a protrusion 100 that is adapted to be slidably guided within slot 102 of a bracket 104 which is mounted by screws 106 and 108 to the sewing machine frame. Rocker arm 98 is attached by any suitable means to the extending portion or shaft 108 of the control means 52.

The shaft 108 of the control means 52 is slidably mounted therein and has a spring 110 retained thereon by a pin 112. The spring 110 functions to bias the control means 52 and the contactor arm 76 to their neutral position by exerting an equal pressure against the wheels 90 and 92 through the rocker arm 98. The central portion of shaft 108 has an insulated block 114 affixed thereto by means of a rivet 113 as shown in FIG. 3. An electrically conductive spring contact finger 115 is riveted by a rivet 116 to the insulated block 114 and functions to provide a conductive path between the carbon resistance element 118 and the electrically conductive bar 120 mounted within the control means 52 on an insulated board 122. The bar 120 and resistance element 118 are provided with terminals 124, 125, etc., (FIG. 3) extending through to the underside of the insulated board 122, which is utilized for mounting components such as, for example, a resistor 126.

Additionally provided in the control means 52 is a switch 127 which is biased to the open position by the spring 110. Switch 127 is held open by a protrusion 129, on the insulated block 114 which functions to remove voltage from the circuit means 44, as will be explained in conjunction with FIG. 5. The control means 52 is fixedly mounted to the sewing machine frame by screws 128 and 130 inserted through holes provided in the flanges 132 and 134 of the control means case 133.

In the preferred embodiment of the invention, the knob 38 has a gear 136 affixed thereto by means of a pin 135. Gear 136 is adapted to mesh with gear 72. Both the knob 38 and the gear 136 are affixed to the sewing machine frame by means of a shoulder screw 140 inserted through a hole 138 provided in the knob and gear which permits them to be journaled about the shoulder screw 140.

In the preferred embodiment of the invention, the knob 38 is provided with a flat protruding portion 142 which is designed to interfere with a portion 144 of the sewing machine frame thereby limiting the travel of knob 38 in the upward direction. Movement of the knob 38 in the upward direction is designed to cause the motor 35 to reverse its direction and thereby, reverse the direction that the drive shaft 39 and the needle bar 24 were traveling. The downward movement of knob 38 is limited by a stop 46 which is mounted, via a screw 148, to the bracket 104 and designed to interfere with contactor arm 76, thereby limiting its travel. Movement of knob 38 in a downward direction is designed to cause the motor 35 to continue in the same direction that it was moving, which is the same direction as it would normally rotate when energized by the foot controller 42.

Referring now to FIG. 5, there is shown a schematic circuit diagram of a preferred embodiment of the present invention. The operator-actuated foot controller 42 which is adapted to be connected to the sewing machine base 12, as noted earlier, contains solid state circuit means including a potentiometer 159, a power control switch 160, and an insulated board, not shown, upon which printed circuit wiring is deposited in a conventional manner. Mounting means, not shown, are also provided for a silicon controlled rectifier (SCR) diodes 152 and 153; resistors 154 and 155; capacitors 156 and 157; and an adjustable resistor 158. The cover of the foot controller, not shown, is coupled to the potentiometer 159 and controls the speed of the motor in a conventional manner. The control means of the foot controller 42 is similar to the control means 52 mounted within the sewing machine frame 11.

The printed circuit conductors within the foot controller 42 are connected to provide a path for the AC power to be coupled, via the switch 160 and the SCR 150 to the armature 161 and field 162 windings of motor 35, which are connected in series to the other side of the AC power source, not shown. A voltage divider is provided by the series connection of a diode 152, a resistor 154, a potentiometer 159 and a resistor 155 connected from the anode electrode of SCR 150 to the common connection 164 between the armature 161 and field 162 windings. Diode 152 rectifies the AC current in the voltage divider changing it to half wave DC, thereby reducing its power consumption. Capacitor 156 is connected in parallel with the series connection of potentiometer 159 and resistor 155 and filters the rectified AC voltage to provide a DC voltage, which is coupled via a diode 153, to the gate electrode of SCR 150. A capacitor 157 is coupled in parallel with the adjustable resistor. 158 across the gate and cathode electrodes of SCR 150 to insure reliable firing of the SCR and, thereby, variable speed control in a conventional manner.

As noted earlier the operator-actuated foot controller 42 is coupled to the frame 11, via a cable and plug 41 adapted to cooperate with the socket 40 on the sewing machine frame 11 and which also is coupled to the source of AC power. An alternate embodiment may provide a separate second plug and cable assembly 166 which has one end adapted to be connected to a source of AC energy or power, not shown, and may be connected on its other end to a socket 168 located on the sewing machine frame 11.

It is to be noted that if two plugs and sockets are used, as in the alternate preferred embodiment described in FIG. 5, removing the operator-actuated foot controller from the sewing machine permits the AC power to remain coupled to the sewing machine for operation by means of the hand-operated knob 38.

In the preferred embodiment of the invention, the sewing machine motor 35, the solid state circuit means 44, the relay 43, and the printed circuit switch mechanism 50 are mounted within the sewing machine frame 11 as noted earlier. The solid state circuit means 44 includes an SCR 180, diodes 181 and 182, capacitors 183 and 184, resistors 185 and 186, adjustable resistor 187 and potentiometer 188, all of which correspond to the SCR 150, diodes 152 and 153, capacitor 156 and 157, resistors 154 and 155, adjustable resistor 158 and potentiometer 159, of the operator-actuated foot controller and functions in the same manner as described earlier to control the speed of the sewing machine motor 35;

Potentiometer 188 is adapted to be controlled by the hand-actuated control knob 38 while the potentiometer 159 is controlled in a'conventional manner by a foot-actuated housing cover, not shown. It is to be noted that actuation of the hand control knob 38, in either a forward or reverse direction, will disable the operator-actuated foot controller 42, so that if a slow speed is desired by the operator during the hand control of the knob 38, the foot controller cannot inadvertently or accidentally increase the speed of the motor or change its direction. The hand control knob always controls the speed and the direction of the motor, regardless of the position of the foot controller. In addition, the energization of the voltage dividers is determined by the position of contacts 206, 207 and 208 of relay 43 which is controlled by control knob 38.

In normal operation of the sewing machine by means of the foot controller 42, the AC current is coupled from one side of the power source, not shown, to the sewing machine motor, via plug and cable 166, normally open switch 36, which must be closed by the operator to energize the circuitry, normally closed contacts 190 and 191 of relay 43, socket 40, plug 41, normally open switch 160 which is.closed when the foot controller cover is depressed, SCR159, normally closed contacts 192 and 193 and normally closed printed circuit contacts 194 and 195, the armature winding 161, normally closed printed circuit contacts 196 and 197, the field winding 162, to the other side of the AC power source, not shown, via the cable and plug 166. Furtherdepressing the foot controller by the operator increases the voltage coupled from the potentiometer 159, via diode 153, to the gate electrode of the SCR 150, thereby increasing the motor speed in a conventional manner.

When the sewing machine is activated by the knob 38 in a downwardly direction, which is the normal or forward direction of motor drive, the power is coupled from one side of the AC line, via the normally open switch 36, which must be moved to the closed position by the operator to energize the circuitry, normally open contacts 190 and 198, which are now closed since the normally open printed circuit contacts 200 and 202 are now closed and provide voltage to energize the relay 43, normally open switch 127 which is closed when the operator moves the knob 38, SCR 180, normally open contacts 203 and 193 which are now closed because relay 43 is energized, printed circuit contacts 194 and 195, armature field winding 161, printed circuit contacts 205 and 197, field winding 162, plug and cable 166 to the other side of the AC line. Additional pressure in the downwardly direction increases the voltage coupled from the potentiometer 188, via diode 182 to the gate electrode of SCR 180, thereby firing the SCR earlier in the AC cycle and increasing the motor speed in a conventional manner.

When the sewing machine is activated by the knob 38 in an upwardly direction, which is the reverse direction of motor drive, the power is coupled from one side of the AC line, via the switch 36, normally open contacts 190 and 198, which are now closed since the normally open printed circuit contacts 200 and 201 are closed and provide voltage to energize the relay 43, switch 127, SCR 180, contacts 203 and 193, printed circuit contacts 194 and 204, armature winding 161, printed circuit contacts 205 and 197, field winding 162, plug and cable 166, to the other side of the AC line. Additional pressure in the upwardly direction increases the voltage coupled from the potentiometer 188, via diode 182, to the gate electrode of SCR 180, thereby, firing the SCR earlier in the AC cycle and increasing the motor speed in a conventional manner.

Note that the preferred embodiment of the invention includes the use of a relay 43 in addition to the printed circuit switch mechanism 50. Although the printed circuit switch mechanism is capable of providing all of the required circuit connections for operation by a conventional arrangement of the printed circuit switch contacts, for convenience, it may be desirable for some of the circuit connections to be accomplished by a conventional relay that is energized by the printed circuit switch mechanism, as shown in FIG. 5. Also, note that an alternate type of printed circuit switch construction may be utilized. This construction is shown in FIG. 6. The alternate printed circuit switch construction is similar to the construction used in the control means 52, and is within the scope of this invention. The alternate type of construction provides for an additional printed circuit conductor on the board member 54 for each pole of the switch. The contactor arm 76 is provided with shorting contacts 172 which complete an electrical connection from the additional printed circuit conductor 170 to the printed circuit conductors 59 or 60. This allows allof the wires 63 to be connected to the printed circuit conductors on the board and none to the contactor arm 76, thereby increasing reliability since none of the wires is required to be flexed.

Hereinbefore has been disclosed an improved sewing machine which utilizes a printed circuit switch and a solid state motor speed control means whereby the sewing machine mechanism may selectively be operated in a forward or reverse direction without the use of a convntional handwheel. The sewing machine may also be operated in both a forward or reverse direction without the use of the conventional operator-actuated foot controller.

Having thus set forth the nature of the invention what is claimed herein is:

1. A sewing machine having a frame including a bed and a hollow standard rising therefrom, stitch forming instrumentalities and work feeding mechanism, a mainshaft operatively connected to said stitch forming instrumentalities and said work feeding mechanism, an electric motor operatively connected to said mainshaft, an operator-actuated foot controller for regulating the speed of operation of said motor, solid state circuit means coupled to said motor and controller and having terminals adapted to .be connected to an external source of electrical energy, and variable speed switch means fixedly mounted within said sewing machine frame and coupled to said motor and said solid state circuit means for driving said motor in a forward and reverse direction.

2. A sewing machine according to claim 1 wherein said variable speed switch means comprises:

a. an insulated board member fixedly mounted within said standard having a plurality of electrical switch contacts thereon, said contacts being adapted to be connected to said circuits means;

b. a contactor arm member rotatably mounted parallel to said board member bearing electrical switch contacts for cooperation with said board switch contacts, the position of said contactor arm member determining which of said switch contacts are made or broken to effect the different operating conditions of said motor;

c. control means coupled to said solid state circuit means and having a slidably mounted extending portion adapted to cooperate with said contactor arm; 1

d. spring means adapted to cooperate with said extending portion and said contactor arm for biasing said extending portion and said contactor arm to a neutral position; and

e. actuating means coupled to said contactor arm,

whereby urging said actuating means in a first direction effects the position of said switch contacts causing said motor to operate in a forward direction and urging said actuating means in a second direction effects the position of said switch contacts causing said motor to operate in a reverse direction.

3. A sewing machine according to claim 2 wherein said actuating means causes said control means to increase the speed of said motor proportional to the distance said actuating means is moved.

4. A sewing machine according to claim 2 wherein said actuating means causes said switch contacts to deenergize said operator actuated foot controller when moved from the neutral position.

5. A sewing machine according to claim 2 further including a second solid state circuit means, fixedly mounted within said sewing machine frame and coupled to said motor, said second circuit means including said control means and having terminals adapted to be connected to said external source of electrical energy and to said switch contacts and being energized when said actuating means and said contactor arm are moved from the neutral position.

6. A sewing machine according to claim 2 wherein said switch means further includes contacts for deenergizing said foot controller when said actuating means is urged in either said first or second direction.

7. A sewing machine according to claim 2 further including a relay means fixedly mounted upon said sewing machine frame, said relay means being energized by said switch contacts and having contacts adapted to energize and de-energize said foot controller.

8. A sewing machine according to claim 5 further including connector means for removing said foot controller and permitting an operator to operate said sewing machine by utilizing said actuating means.

9. In a sewing machine having a frame including a bed and a hollow standard rising therefrom, stitch forming instrumentalities and work feeding mechanism, a main shaft operatively connected to said stitch forming instrumentalities and said work feeding mechanism, an electric motor operatively connected to said main shaft, an operator actuated foot controller for regulating the speed of operation of said motor, and solid state circuit means coupled to said motor and controller and having terminals adapted to be connected to an external source of electrical energy, the improvement comprising:

a. an insulated board member fixedly mounted within said standard having a plurality of electrical switch contacts thereon, said contacts being adapted to be connected to said circuit means;

b. a contactor arm member rotatably mounted parallel to said board member bearing electrical switch contacts for cooperation with said board switch contacts, the position of said contactor arm member determining which of said switch contacts are made or broken to effect the different operating conditions of said motor;

c. control means coupled to said solid state circuit means and having a slidably mounted extending portion adapted to cooperate with said contactor arm;

d. spring means adapted to cooperate with said extending portion and said contactor arm for biasing said extending portion and said contactor arm to a neutral position; and

e. actuating means coupled to said contactor arm, whereby urging said actuating means in a first direction effects the position of said switch contacts causing said motor to operate in a forward direction and urging said actuating means in a second direction effects the position of said switch contacts causing said motor to operate in a reverse direction. 

1. A sewing machine having a frame including a bed and a hollow standard rising therefrom, stitch forming instrumentalities and work feeding mechanism, a main-shaft operatively connected to said stitch forming instrumentalities and said work feeding mechanism, an electric motor operatively connected to said mainshaft, an operator-actuated foot controller for regulating the speed of operation of said motor, solid state circuit means coupled to said motor and controller and having terminals adapted to be connected to an external source of electrical energy, and variable speed switch means fixedly mounted within said sewing machine frame and coupled to said motor and said solid state circuit means for driving said motor in a forward and reverse direction.
 2. A sewing machine according to claim 1 wherein said variable speed switch means comprises: a. an insulated board member fixedly mounted within said standard having a plurality of electrical switch contacts thereon, said contacts being adapted to be connected to said circuits means; b. a contactor arm member rotatably mounted parallel to said board member bearing electrical switch contacts for cooperation with said board switch contacts, the position of said contactor arm member determining which of said switch contacts are made or broken to effect the different operating conditions of said motor; c. control means coupled to said solid state circuit means and having a slidably mounted extending portion adapted to cooperate with said contactor arm; d. spring means adapted to cooperate with said extending portion and said contactor arm for biasing said extending portion and said contactor arm to a neutral position; and e. actuating means coupled to said contactor arm, whereby urging said actuating means in a first direction effects the position of said switch contacts causing said motor to operate in a forward direction and urging said actuating means in a second direction effects the position of said switch contacts causing said motor to operate in a reverse direction.
 3. A sewing machine according to claim 2 wherein said actuating means causes said control means to increase the speed of said motor proportional to the distance said actuating means is moved.
 4. A sewing machine according to claim 2 wherein said actuating means causes said switch contacts to de-energize said operator actuated foot controller when moved from the neutral position.
 5. A sewing machine according to claim 2 further including a second solid state circuit means, fixedly mounted within said sewing machine frame and coupled to said motor, said second circuit means including said control means and having terminals adapted to be connected to said external source of electrical energy and to said switch contacts and being energized when said actuating means and said contactor arm are moved from the neutral position.
 6. A sewing machine according to claim 2 wherein said switch means further includes contacts for de-energizing said foot controller when said actuating means is urged in either said first or second direction.
 7. A sewing machine according to claim 2 further including a relay means fixedly mounted upon said sewing machine frame, said relay means being energized by said switch contacts and having contacts adapted to energize and de-energize said foot controller.
 8. A sewing machine according to claim 5 further including connector means for removing said foot controller and permitting an operator to operate said sewing machine by utilizing said actuating means.
 9. In a sewing machine having a frame including a bed and a hollow standard rising therefrom, stitch forming instrumentalities and work feeding mechanism, a main shaft operatively connected to said stitch forming instrumentalities and said work feeding mechanism, an electric motor operatively connected to said main shaft, an operator actuated foot controller for regulating the speed of operation of said moTor, and solid state circuit means coupled to said motor and controller and having terminals adapted to be connected to an external source of electrical energy, the improvement comprising: a. an insulated board member fixedly mounted within said standard having a plurality of electrical switch contacts thereon, said contacts being adapted to be connected to said circuit means; b. a contactor arm member rotatably mounted parallel to said board member bearing electrical switch contacts for cooperation with said board switch contacts, the position of said contactor arm member determining which of said switch contacts are made or broken to effect the different operating conditions of said motor; c. control means coupled to said solid state circuit means and having a slidably mounted extending portion adapted to cooperate with said contactor arm; d. spring means adapted to cooperate with said extending portion and said contactor arm for biasing said extending portion and said contactor arm to a neutral position; and e. actuating means coupled to said contactor arm, whereby urging said actuating means in a first direction effects the position of said switch contacts causing said motor to operate in a forward direction and urging said actuating means in a second direction effects the position of said switch contacts causing said motor to operate in a reverse direction. 